Coded modulation is a bandwidth efficient scheme that combines the functions of coding and modulation. Low Density Parity Check (LDPC) codes have attracted wide research interests owing to their relatively low decoding complexity, while maintaining a comparable performance to that of the best known channel codes, namely turbo codes. In this contribution we proposed an LDPC assisted Block Coded Modulation (LDPC-BCM) scheme for transmission over Rayleigh fading channels, which requires no bandwidth expansion. The performance of the proposed LDPC-BCM scheme will be compared to that of similar throughput Turbo Trellis Coded Modulation (TTCM) schemes. Specifically, 1, 2 and 3 bit per symbol effective throughput Quadrature Phase Shift Keying (QPSK), 8-level Phase Shift Keying (8PSK) and 16-level Quadrature Amplitude Modulation (16QAM) are studied in comparison to the corresponding TTCM benchmarkers. Furthermore, we comparatively study the associated decoding complexity. It is shown that owing to its block-based structure which is capable of overbridging deep channel fades, LDPC-BCM constitutes a better solution for transmission over hostile Rayleigh fading channels than TTCM, in particular when the system’s affordable delay is limited.

Abstract

Coded modulation is a bandwidth efficient scheme that combines the functions of coding and modulation. Low Density Parity Check (LDPC) codes have attracted wide research interests owing to their relatively low decoding complexity, while maintaining a comparable performance to that of the best known channel codes, namely turbo codes. In this contribution we proposed an LDPC assisted Block Coded Modulation (LDPC-BCM) scheme for transmission over Rayleigh fading channels, which requires no bandwidth expansion. The performance of the proposed LDPC-BCM scheme will be compared to that of similar throughput Turbo Trellis Coded Modulation (TTCM) schemes. Specifically, 1, 2 and 3 bit per symbol effective throughput Quadrature Phase Shift Keying (QPSK), 8-level Phase Shift Keying (8PSK) and 16-level Quadrature Amplitude Modulation (16QAM) are studied in comparison to the corresponding TTCM benchmarkers. Furthermore, we comparatively study the associated decoding complexity. It is shown that owing to its block-based structure which is capable of overbridging deep channel fades, LDPC-BCM constitutes a better solution for transmission over hostile Rayleigh fading channels than TTCM, in particular when the system’s affordable delay is limited.